1) Field of the Invention
The present invention relates generally to cotton harvesters, and more specifically to an improved cotton picker row unit structure.
2) Related Art
In the past, cotton harvesters of the spindle type such as the John Deere model 9910 Cotton Picker included row units with front and rear picker drums located to pick cotton from the opposite sides of the row. The forward drum typically included 16 upright bars of spindles and the rear drum had 12 bars of spindles. This configuration of drums required a relatively wide housing which limited the harvester to harvesting only two widely spaced (38 or 40 inches) rows. Recently, narrow row cotton harvesters which are capable of harvesting four or more rows of cotton spaced as narrowly as 30 inches have been commercially available. One type of narrow row harvester, exemplified by the Case-IH model 2055 Cotton Picker, has nested units with two 12-bar drums on opposite sides of the row. A second type of narrow row harvester, exemplified by the John Deere model 9960 Cotton Picker, utilizes two 12-bar drums located one behind the other on the same side of the row.
The standard row units contain upright moistener columns positioned forwardly of the front and rear drums. The columns include a series of pads, such as shown in U.S. Pat. No. 4,821,498 of common ownership with the present application, supported above the rows of spindles. A fluid line leading to a nozzle and distributor in the upper row unit housing delivers cleaning solution to the pads which, with the scrubbing action of the pads, helps keep the spindles clean. Proper cleaning is necessary to ensure maximum spindle picking efficiency and doffing. The moistener pads must be periodically replaced since they are subject to wear from constant contact with the spindles. Spindles wrapped with cotton can damage or remove pads from the column. Severely wrapped spindles will not pass through the moistener column and as a result cause the drum clutch to slip. The wrapped spindles must be accessed and the wraps removed before the unit can be restarted.
Servicing the moistener column and wrapped spindles has been a continuing source of difficulty with most available row units. Wrapped spindles often cannot clear the moistener pads and therefore prevent rotation of the drum for better access to the wrapped spindles.
Often, the upper housing area of the unit must be accessed to check the fluid nozzle and distributor of the moistener system. The nozzle and distributor are subject to contamination from the grease and dirt in the upper housing.
Other problems with conventional moistener columns include insufficient spindle time in the moistener column and moistener pad fin misalignment relative to the spindle barbs, both of which lead to less effective spindle cleaning. The moistener column location is at a point where picker bars accelerate for reentry into the row and so pass quickly through the column. The angle of the spindle relative to the moistener pad fins reduces cleaning action between the barbs.
A further problem with the moistener columns, especially in tandem drum units, is that the row unit length must be extended to accommodate the columns. The forward drum has to be spaced a sufficient distance ahead of the rear drum so that the rear moistener column does not interfere with the spindles on the forward drum. The forward extremity of the unit housing must also be extended a sufficient distance in the forward direction to accommodate the moistener column for the front drum. As a result, the length of the row unit is increased and the center of gravity of the unit is extended forwardly, which reduces maneuverability and adversely affects load distribution. In commonly owned copending application Ser. No. 07/849,925, filed Mar. 12, 1992 and entitled "HIGH SPEED TWO-DRUM ROW UNIT FOR A COTTON HARVESTER", a row unit is shown wherein the front drum cam is angled relative to the forward direction to facilitate closer placement of the drums and reduce row unit length. However, length reduction is hindered by the rear moistener column in that row unit.